Re: [PATCH v2 4/6] usb: roles: add API to get usb_role_switch by node

[Heikki Krogerus]

Hi Chunfeng,

On Fri, Mar 15, 2019 at 05:13:24PM +0800, Chunfeng Yun wrote:
> I encounter a build error when CONFIG_USB_ROLE_SWITCH is not enabled,
> 
> drivers/usb/mtu3/mtu3_dr.o: In function `ssusb_role_sw_register':
> ./drivers/usb/mtu3/mtu3_dr.c:460: undefined reference to
> `usb_role_switch_register'
> drivers/usb/mtu3/mtu3_dr.o: In function `ssusb_otg_switch_exit':
> ./drivers/usb/mtu3/mtu3_dr.c:491: undefined reference to
> `usb_role_switch_unregister'

So you need to add dependency on USB_ROLE_SWITCH, right?

--- a/drivers/usb/mtu3/Kconfig
+++ b/drivers/usb/mtu3/Kconfig
@@ -43,6 +43,7 @@ config USB_MTU3_DUAL_ROLE
        bool "Dual Role mode"
        depends on ((USB=y || USB=USB_MTU3) && (USB_GADGET=y || USB_GADGET=USB_MTU3))
        depends on (EXTCON=y || EXTCON=USB_MTU3)
+       depends on USB_ROLE_SWITCH
        help
          This is the default mode of working of MTU3 controller where
          both host and gadget features are enabled.

> the following patch has fixed the issue, but seems not get into kernel,
> [v3,08/12] usb: roles: Add usb role switch notifier.
> https://patchwork.kernel.org/patch/10836525/

I don't understand how that fixes the problem? That patch will in any
case be targeting v5.2. We are in the middle of merge window, so
nothing is happening until v5.1-rc1 is tagged.


thanks,

-- 
heikki